Modular steel bridge

ABSTRACT

A modular steel bridge is configured by combining at least two steel girder segments, and it includes a bearing block installed to be connected to an upper flange of a connection end of each steel girder segment and a web, and a hinge assembly installed to be attachable to the lower flange of each connection end and hinge-connecting the connection ends.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a modular steel bridge. Moreparticularly, the present invention relates to a modular steel bridgethat is generated by connecting steel girder segments in a hinge format.

(b) Description of the Related Art

In general, a modular steel bridge is a temporary bridge in the simplebridge or continuous bridge format, and it has a structure in which atleast two steel girder segments are connected as a single body.

The steel girders are generally manufactured as segments so as toincrease the conveyance limit and increase installation convenience, andthe segments are generally connected by welds or bolts at theconstruction site.

Regarding constructing the modular steel bridge, connection of girdersegments by welding improves appearance of the entire structure comparedto connection by bolts, and simultaneously reduces the overall steelamount since it requires no splice plate.

However, the on-the-spot welding has a large generation frequency ofdefects, it is difficult to improve defect parts, and it may greatlyInfluence temporary precision because of shrinkage of the weldedstructure. Also, it has a drawback of increasing the amount ofnondestructive inspection because of the reliability of the on-the-spotwelding.

The connection of girder segments by bolts is less influenced by atechnician's skillfulness and job conditions than connection by welding,it is relatively easy to control the quality of connected parts, andhence it is the most frequently used.

However, it takes much time to engage a plurality of bolts at theconstruction site, and the introduced axial force of the bolt is greatlychanged by the engagement method and engagement order. Particularly, inthe case of a friction joint, since members are connected by usingfrictional force of the contacting surface, close attention is requiredso as to acquire the friction coefficient of the steel surface.

Connection specifications of the hinge structure have been recentlydeveloped so as to improve resolution of the problems of weldingconnection and bolt connection of girder segments and to apply theconnection specifications at an area that requires rapid constructionsuch as for an emergency bridge.

The connection specifications result in a structure that can resist aload applied to the compression unit of a girder segment through apredetermined reinforcing member, and that can resist a load applied tothe tensile unit of the girder segment through a hinge structure.

However, as the hinge structure of the modular steel bridge having theabove-noted connection specification structure is connected to theconnection part of the girder segment through welding, fatigue failurecan be easily generated at the welded part by repeated loads during useof the girder.

Also, when a crack occurs in the hinge structure, it is impossible torepair the cracked part and reconstruction of the entire girder isneeded.

In addition, the modular steel bridge having the above-noted connectionspecification has a problem of manufacturing the hinge structure byusing an ultra-thick plate with a thickness of greater than 100 mm so asto resist the tensile force applied to the hinge structure.

It is difficult to buy the ultra thick plates from domestic shops inKorea, but it is possible to manufacture the hinge structure throughcasting and forging as a substitute for the ultra thick plate, whichhowever is not a desirable solution since the production cost issubstantially increased.

Further, the modular steel bridge having the conventionalhinge-structured connection specification has a less stable structure,and hence, when the hinge structure generates a crack as a result ofrepeated loads, the girder structure may dramatically fail.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide a modularsteel bridge having advantages of preventing fatigue failure that occursat a welded part of the girder segment and the hinge structure, andallowing easy partial repair of a hinge structure in which a crack isgenerated.

The present invention has been made in another effort to provide amodular steel bridge having advantages of reducing the design thicknessof a hinge structure to be less than 100 mm and dividing a tensile forcemainly applied to the hinge structure under the loading,

In one aspect of the present invention, a modular steel bridgeconfigured by connecting at least two steel girder segments includes abearing block installed to be connected to an upper flange of aconnection end of the steel girder segment and a web, and a hingeassembly that is installed to be attachable to a lower flange of theconnection end for hinge-combining the connection end.

The hinge assembly includes a connecting plate installed to be connectedto the lower flange of the connection end by using bolts and nuts, and acombining member fixedly installed at the connecting plate andcomplementarily hinge-combined by a hinge pivot.

The lower flange of the connection end and the connecting plate areformed with a plurality of bolt holes.

The combining member includes a first hinge plate being fixedlyinstalled at one connecting plate and having a pair of combining holesto which the hinge pivot is combined, and a second hinge plate beingfixedly installed at another connecting plate, having a combining holeto which the hinge pivot is combined, and being combined with the firsthinge plate in a concavo-convex manner.

The hinge pivot is formed with pin holes into which hinge pins areinserted at both ends thereof.

The connecting plate is installed to be connected to the bottom part ofthe lower flange, and the combining member is installed to be fixed tothe bottom part of the connecting plate.

In another aspect of the present invention, a modular steel bridgeconfigured by connecting at least two steel girder segments includes abearing block installed at a connection end of a steel girder segment, ahinge assembly installed at the connection end, and a reinforcing unitinstalled to be connected to the connection end and dividing a tensileforce applied to the hinge assembly.

The bottom part of the web of the connection end is cut to apredetermined height, and the hinge assembly is installed to be fixed atthe cutting part of the web and the top part of the lower flange.

The hinge assembly includes: a first hinge plate installed to be fixedat the cutting part of the web of the connection end of one steel girdersegment and the top part of the lower flange, and having a pair ofcombining holes to which a hinge pivot is combined; and a second hingeplate installed to be fixed at the cutting part of the web of theconnection end of the other steel girder segment and the top part of thelower flange, having a combining hole to which the hinge pivot iscombined, and being combined with the first hinge plate in theconcavo-convex manner.

The hinge pivot has pin holes into which hinge pins are inserted at bothends thereof.

The first hinge plate and the second hinge plate include a combiningunit to which the hinge pivot is combined.

The combining unit protrudes outside each connection end and is extendedbetween the lower flanges.

The reinforcing unit includes a steel rod installed to be connected tothe lower flanges of the connection ends.

The reinforcing unit includes a fixing member being installed at eachlower flange of the connection ends and supporting respective ends ofthe steel rod, and a nut combined to each end of the steel rod.

The reinforcing unit includes a steel plate installed to be connected toeach lower flange of the connection ends.

The reinforcing unit includes a connecting member being installed ateach lower flange and supporting the steel plate.

The steel plate is installed to be connected to each connecting memberby using bolts and nuts.

The steel plate is installed to be welded and fixed to each connectingmember.

A bearing block is fixedly installed to the upper flange of eachconnection end and each web.

The connection ends of the steel girder segments are arranged with a gaptherebetween, and the bearing blocks are installed to contact eachother.

The bearing blocks are is installed to protrude into a gap space betweenthe connection ends.

The upper flange of each connection end is cut to a predeterminedlength, and the top part of the web of each connection end is cut to apredetermined height.

Each bearing block is formed to be thicker than the upper flange, and iswelded and fixed at the cutting parts of the upper flange and the web.

Each steel girder segment includes one of an I-type girder, a boxgirder, and a

-type girder.

BRIEF DESCRIPTION OF THE DRAWINGS

Subsequent drawings are provided to be referred to for the descriptionof an exemplary embodiment of the present invention, and the scope ofthe present invention Is not to be restricted by the accompanyingdrawings.

FIG. 1 is an exploded perspective view for a modular steel bridgeaccording to a first exemplary embodiment of the present invention.

FIG. 2 is a front schematic diagram of FIG. 1.

FIG. 3 is a side schematic diagram for a modular steel bridge accordingto a second exemplary embodiment of the present invention.

FIG. 4 is a side schematic diagram for a modular steel bridge accordingto a third exemplary embodiment of the present invention.

FIG. 5 is an exploded perspective view for a modular steel bridgeaccording to a fourth exemplary embodiment of the present invention.

FIG. 6 is a front schematic diagram of FIG. 5.

FIG. 7 is a front schematic diagram for a modular steel bridge accordingto a fifth exemplary embodiment of the present invention.

FIG. 8 is a front schematic diagram for a modular steel bridge accordingto a sixth exemplary embodiment of the present invention.

FIG. 9 is a front schematic diagram for a modular steel bridge accordingto a seventh exemplary embodiment of the present invention.

FIG. 10 is a side schematic diagram for a modular steel bridge accordingto an eighth exemplary embodiment of the present invention.

FIG. 11 is a side schematic diagram for a modular steel bridge accordingto a ninth exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. As those skilled in the art would realize,the described embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the present invention.

FIG. 1 is an analyzed perspective view for a modular steel bridgeaccording to a first exemplary embodiment of the present invention, andFIG. 2 is a front schematic diagram of FIG. 1.

Referring to the drawings, the modular steel bridge 100 is a temporarybridge in the simple bridge or continuous bridge format, and has astructure in which at least two steel girder segments 10 are connectedwith each other.

The steel girder segments 10 are manufactured in a factory in advance,are delivered to the construction site, and are then connected.

Here, each steel girder segment 10 includes an upper flange 11, a lowerflange 13, and a web 15 for connecting the flanges 11 and 13.

In this instance, each steel girder segment 10 is provided as an I-typegirder in which the upper flange 11 and the lower flange 13 are arrangedin parallel at the top part and the bottom part of the web 15 that isarranged in the vertical direction.

The modular steel bridge 100 includes a bearing block 30 that isinstalled to be connected to a connection end of each steel girdersegment 10, and a hinge assembly 50 attachable to the connection ends sothat the connection ends of the steel girder segments 10 may behinge-connected.

In the modular steel bridge 100, the connection ends of the steel girdersegments 10 are disposed with a gap therebetween, the bearing blocks 30are provided to contact each other, and the connection ends of the steelgirder segments 10 are hinge-combined by the hinge assembly 50.

The bearing blocks 30 resist a compressive force applied at theconnection parts of the steel girder segments 10.

Each bearing block 30 is a metal plate having the same width as theupper flange 11 of the steel girder segment 10 and a greater thicknessthan that of the upper flange 11.

The bearing block 30 is installed to be fixed with the upper flange 11of the connection end of the steel girder segment 10 and the web 15.

For this, a fixture unit 17 is formed at the upper flange 11 of theconnection end of the steel girder segment 10 and the web 15. Thefixture unit 17 includes a part that is generated by cutting the upperflange 11 of the connection end of the steel girder segment 10 to apredetermined length and a part that is generated by cutting the toppart of the web 15 to a predetermined height.

In this instance, the bearing block 30 has a greater length than thecutting part of the web 15 and is arranged on the fixture unit 17.

Therefore, the bearing block 30 is welded and fixed to the upper flange11 and the web 15 while being arranged on the fixture unit 17.

Since the bearing blocks 30 have a greater length than that of thecutting part of the web 15, the bearing blocks 30 partially protrudeinto the gap space between the connection ends of the steel girdersegments 10 and contact each other.

The hinge assembly 50 resists the tensile force applied to theconnection parts of the steel girder segments 10.

The hinge assembly 50 includes a connecting plate 51 that is installedto be connected to the lower flange 13 of the connection end of a steelgirder segment 10, a combining member 53 that is installed to be fixedto the connecting plate 51, and a hinge pivot 71 for hinge-combining thecombining members 53.

The connecting plate 51 includes a metal plate having a predeterminedlength and having the same width as the lower flange 13.

The connecting plate 51 is installed to be connected to the bottom ofthe lower flange 13, and is engaged with the lower flange 13 by bolts 61and nuts 62.

For this, a plurality of bolt holes 51 a for engaging the bolts 61 areformed in the connecting plate 51.

In correspondence to this, the lower flange 13 has a plurality of boltholes 13 a that correspond to the bolt holes 51 a in the connectingplate 51. The combining member 53 has a form of a plate or a block,desirably has the form of a plate, and is welded and fixed on the centerof the bottom of the connecting plate 51.

In detail, the combining member 53 includes a first hinge plate 55 thatis fixedly installed on the bottom of one connecting plate 51, and asecond hinge plate 57 that is fixedly installed on the bottom of theother connecting plate 51 for each steel girder segment 10.

The first hinge plate 55 is formed with a pair of combining parts towhich the hinge pivot 71 is combined.

The combining parts are separately formed with a gap therebetween, andare formed to protrude into the gap space between the connection ends ofthe steel girder segments 10.

Each combining part is formed with a combining hole 55 a into which thehinge pivot 71 can be inserted.

The second hinge plate 57 is combined with the first hinge plate 55 inthe concavo-convex manner, and integrally has a combining part to whichthe hinge pivot 71 is combined.

The combining part is inserted between the combining parts of the firsthinge plate 55, and is formed to protrude into the gap space between theconnection ends of the steel girder segment 10 in a like manner of thefirst hinge plate 55.

The combining part includes a combining hole 57 a into which the hingepivot 71 can be inserted.

In the drawing, the non-described reference numeral 71 a indicates pinholes that are formed at both ends of the hinge pivot 71, and referencenumeral 73 shows hinge pins that are combined with the pin holes 71 a ofthe hinge pivot 71.

Regarding the building process of the modular steel bridge 100, thefixture unit 17 of the connection end of each steel girder segment 10made in the factory is welded to the bearing block 30.

In addition to this, the connecting plate 51 to which the first hingeplate 55 is welded is engaged by the bolts 61 and the nuts 62 on thelower flange 13 of the connection end of one steel girder segment 10.

Also, the connecting plate 51 to which the second hinge plate 57 iswelded is engaged by the bolts 61 and the nuts 62 on the lower flange 13of the connection end of one steel girder segment 10.

When the steel girder segments 10 are delivered to the constructionsite, the operator inserts the combining part of the second hinge plate57 between the combining parts of the first hinge plate 55 to match thecombining holes 55 a and 57 a of the first hinge plate 55 and the secondhinge plate 57.

The hinge pivot 71 is combined with the combining holes 55 a and 57 a ofthe first hinge plate 55 and the second hinge plate 57, and hinge pins73 are inserted into the pin holes 71 a of the hinge pivot 71.

Therefore, through the above-described assemble process, the girderstructure having the connected steel girder segments 10 as a body isgenerated, and the modular steel bridge 100 according to the exemplaryembodiment of the present invention is completed by mounting the girderstructure to form the bridge.

FIG. 3 is a side schematic diagram for a modular steel bridge accordingto a second exemplary embodiment of the present invention.

Referring to FIG. 3, the modular steel bridge 200 includes a box girderas a steel girder segment 210.

A bearing block 230 is installed to be fixed on the top part of theconnection end of the steel girder segment 210, and a pair of hingeassemblies 250 are connected the bottom part of the connection end.

FIG. 4 is a side schematic diagram for a modular steel bridge accordingto a third exemplary embodiment of the present invention.

Referring to FIG. 4, the modular steel bridge 300 includes a

-type girder as a steel girder segment 310.

The steel girder segment 310 includes a pair of webs 315, the top partsof the webs 315 are connected to a steel plate, and the bottom partsthereof are connected to lower flanges 313.

The bearing block 330 is installed to be fixed at the top part of theconnection end of the steel girder segment 310, and a hinge assembly 350is connected to the lower flange 313 of the connection end.

FIG. 5 is an analyzed perspective view for a modular steel bridgeaccording to a fourth exemplary embodiment of the present invention, andFIG. 6 is a front schematic diagram of FIG. 5.

As shown, the modular steel bridge 400 includes a bearing block 430installed at the connection end of each steel girder segment 410, ahinge assembly 450, and a reinforcing unit 470.

The modular steel bridge 400 is arranged so that connection ends ofsteel girder segments 410 may be arranged with a gap therebetween andare hinge-combined by the hinge assembly 450, the bearing blocks 430 areinstalled to contact each other, and a load applied to the hingeassembly 450 is shared with the reinforcing unit 470.

In this instance, the bearing block 430 will not be described since itcorresponds to the configuration of the previous exemplary embodiment.

The hinge assembly 450 resists the tensile force applied to theconnection part of the steel girder segment 410.

The hinge assembly 450 is installed to be fixed at a lower flange 413 ofthe connection end of each steel girder segment 410 and a web 415.

In detail, the hinge assembly 450 includes a first hinge plate 455 thatis fixedly installed at the lower flange 413 of the connection end ofone steel girder segment 410 and the web 415, and a second hinge plate457 that is fixedly installed at the lower flange 413 of the connectionend of the other steel girder segment 410 and the web 415.

In addition to this, the hinge assembly 450 includes a hinge pivot 461for hinge-combining the first hinge plate 455 and the second hinge plate457.

In this instance, the first hinge plate 455 and the second hinge plate457 are respectively installed and welded to be fixed at the top surfaceof the lower flange 413 of the connection end of each steel girdersegment 410 and web 415.

For this, the web 415 of the connection end of each steel girder segment410 forms an accepting unit 419 for arranging the first hinge plate 455and the second hinge plate 457, respectively.

Each accepting unit 419 is formed by a space between a part that isgenerated by cutting the bottom part of the web 415 to a predeterminedheight and the lower flange 413.

Therefore, the first hinge plate 455 and the second hinge plate 457,while being arranged in the respective accepting units 419, are weldedand fixed at the top surface of the lower flange 413 and the cuttingpart of the web 415.

The first hinge plate 455 integrally forms a pair of combining units 455b to which the hinge pivot 461 is combined.

The combining units 455 b are formed with a gap therebetween, andprotrude outside the connection end of one steel girder segment 410.

Each combining unit 455 b has a combining hole 455 a in which the hingepivot 461 can be inserted.

The second hinge plate 457 is combined with the first hinge plate 455 inthe concavo-convex manner, and integrally forms a combining unit 457 bto which the hinge pivot 461 is combined.

The combining unit 457 b is inserted between the combining units 455 bof the first hinge plate 455, and protrude outside the connection end ofthe steel girder segment 410 in a like manner of the first hinge plate455.

The combining unit 457 b is formed with a combining hole 457 a intowhich the hinge pivot 461 can be inserted.

In the drawing, the non-described reference numeral 461 a indicates pinholes generated at both ends of the hinge pivot 461, and referencenumeral 463 indicates hinge pins that are combined to the pin holes 461a of the hinge pivot 461.

The reinforcing unit 470 shares the tensile force that is mainly appliedto the hinge assembly 450. The reinforcing unit 470 includes a steel rod471 that is installed to be connected to the lower flange 413 of theconnection end of each steel girder segment 410, fixing members 473 forsupporting respective ends of the steel rod 471, and nuts 475 that arescrew-combined to each end of the steel rod 471.

The steel rod 471 receives a substantial part of the tensile forceapplied to the hinge assembly 450, and is arranged in the lengthdirection of the steel girder segment 410 with the connection ends ofthe facing steel girder segments 410 at the center.

A screw thread 471 a for engaging the nuts 475 is formed at each end ofthe steel rod 471.

The fixing member 473 is installed to be welded and fixed at the bottompart of the lower flange 413 of the connection end of each steel girdersegment 410.

Each fixing member 473 is formed with a hole 473 a into which an end ofthe steel rod 471 is inserted.

In this instance, as shown in the drawing, each fixing member 473includes a vertical steel plate that is vertically fixed on the bottomof the lower flange 413, and a side steel plate of a triangular rib formthat is fixedly installed at both ends of the vertical steel plate andthe bottom of the lower flange 413.

However, the fixing member 473 can also be formed in a box form withoutbeing restricted to the above-described configuration.

Regarding the method for assembling the modular steel bridge 400according to the exemplary embodiment of the present invention, thesteel girder segments 410 are manufactured in the factory and are thendelivered to the construction site.

In this instance, the bearing block 430 is welded on a fixture unit 417of the connection end of each steel girder segment 410.

Further, the first hinge plate 455 is arranged at the accepting unit 419of the connection end of one steel girder segment 410, and the firsthinge plate 455 is welded on the top part of the lower flange 413 and acutting part of the web 415.

Also, the second hinge plate 457 is arranged at the accepting unit 419of the connection end of another steel girder segment 410, and thesecond hinge plate 457 is welded on the top part of the lower flange 413and a cutting part of the web 415.

In addition to this, the fixing member 473 is welded on the bottom ofthe lower flange 413 of the connection end of each steel girder segment410.

In this state, the combining holes 455 a and 457 a of the combiningunits 455 b and 457 b are matched by inserting the combining unit 457 bof the second hinge plate 457 between the combining units 455 b of thefirst hinge plate 455.

The hinge pivot 461 is combined with the combining holes 455 a and 457 aof the first hinge plate 455 and the second hinge plate 457, and thehinge pins 463 are inserted into the pin holes 461 a of the hinge pivot461.

The ends of the steel rod 471 are inserted into the holes 473 a of thefixing members 473 such that both ends of the steel rod 471 are combinedwith the fixing member 473.

In this state, a nut 475 is combined with each end of the steel rod 471and is then threaded thereon, and a girder structure in which at leasttwo steel girder segments 410 are integrally connected is completed.

Therefore, when the girder structure is lifted upward so that both endsof the girder structure form the bridge, the construction of the modularsteel bridge 400 according to the exemplary embodiment of the presentinvention is finished.

Accordingly, since the modular steel bridge 400 has a reinforcing unit470 that is installed to be connected to the lower flange 413 of theconnection end of the steel girder segment 410, the tensile force mainlyapplied to the hinge assembly 450 is shared and the design thickness ofthe hinge plate is reduced to be less than 100 mm, differing from theprior art.

FIG. 7 is a front schematic diagram for a modular steel bridge accordingto a fifth exemplary embodiment of the present invention.

As shown, the modular steel bridge 500 includes a hinge assembly 550that is formed for a combining unit 555 b of a first hinge plate 555 anda combining unit 557 b of a second hinge plate 557 to be extendedbetween lower flanges 513.

In detail, the combining unit 555 b of the first hinge plate 555 and thecombining unit 557 b of the second hinge plate 557 protrude outside theconnection ends of the steel girder segments 510 and extend to an areabetween the lower flanges 513 in a like manner of the previous exemplaryembodiment.

That is, the thickness of the combining units 555 b and 557 b of thefirst hinge plate 555 and the second hinge plate 557 is greater than thethickness of the other part excluding the combining units 555 b and 557b by the thickness of the lower flange 513.

Therefore, according to the modular steel bridge 500 of the exemplaryembodiment of the present invention, the tensile force applied to thehinge assembly 550 is more efficiently resisted since the combining unit555 b of the first hinge plate 555 and the combining unit 557 b of thesecond hinge plate 557 are formed to be extended between the lowerflanges 513.

The residual configurations and operations of the modular steel bridge500 according to this exemplary embodiment of the present invention willnot be described since they correspond to those of the previousexemplary embodiment.

FIG. 8 is a front schematic diagram for a modular steel bridge accordingto a sixth exemplary embodiment of the present invention.

As shown, the modular steel bridge 600 can include a reinforcing unit670 including a steel plate 671 that is installed to be connected to thelower flange 613 of the connection end of each steel girder segment 610.

The reinforcing unit 670 includes connecting members 673 for supportingrespective ends of the steel plate 671, and the connecting members 673are installed to be welded and fixed at the bottom surface of the lowerflanges 613 of the connection ends of the steel girder segments 610.

In this instance, the steel plate 671 is integrally connected to theconnecting members 673 by engagement of bolts 675 and nuts 676.

The residual configurations and operations of the modular steel bridge600 according to the exemplary embodiment of the present invention willnot be described since they correspond to those of the previousexemplary embodiments.

FIG. 9 is a front schematic diagram for a modular steel bridge accordingto a seventh exemplary embodiment of the present invention.

Referring to the drawing, the modular steel bridge 700 can be configuredwith a reinforcing unit 770 in which a steel plate 771 is welded toconnecting members 773 on the basis of the configuration of the previousexemplary embodiment.

In detail, the connecting members 773 are installed to be welded andfixed at the bottom part of lower flanges 713, and the steel plate 771is installed to be welded and fixed at the bottom part of the connectingmembers 773.

The residual configurations and operations of the modular steel bridge700 according to the exemplary embodiment of the present invention willnot be described since they correspond to those of the previousexemplary embodiments.

FIG. 10 is a side schematic diagram for a modular steel bridge accordingto an eighth exemplary embodiment of the present invention,

Referring to the drawing, the modular steel bridge 800 includes a boxgirder as a steel girder segment 810.

A bearing block 830 is installed to be fixed at the top part of theconnection end of the steel girder segment 810 according to theexemplary embodiment of the present invention, and a pair of hingeassemblies 850 are installed to be fixed at the bottom part of theconnection end.

FIG. 11 is a side schematic diagram for a modular steel bridge accordingto a ninth exemplary embodiment of the present invention,

Referring to the drawing, the modular steel bridge 900 can adopt a

-type girder as a steel girder segment 910.

The steel girder segment 910 includes a pair of webs 915, a steel plateis integrally connected to the top part of the webs 915, and a lowerflange 913 is integrally connected to each bottom part thereof.

A bearing block 930 is installed to be fixed at the top part of theconnection end of the steel girder segment 910, and a hinge assembly 950is installed to be fixed at each lower flange 913 of the connection end.While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

According to the exemplary embodiment of the present invention, it ispossible to hinge-assemble steel girder segments by using bolts, therebyfundamentally preventing the danger of fatigue failure that occurs at awelding part of a steel girder segment and a hinge structure.

Also, since the hinge assembly is attachable to the steel girdersegment, the steel girder segment can be reused. Further, when a crackoccurs at the hinge assembly because of a repeated load while using thegirder, the maintenance fee of the girder can be reduced since it iseasy to exchange the cracked hinge assembly.

In addition, as a reinforcing unit for dividing the tensile force mainlyapplied to the hinge assembly is provided, there is no need to use aconventional ultra-thick plate for the hinge assembly to thereby reducethe production cost of the bridge.

Also, the stability of the structure against the tensile force mainlyapplied to the hinge assembly can be improved by using the reinforcingunit.

1. A modular steel bridge configured by connecting at least two steelgirder segments, comprising: a bearing block installed to be connectedto an upper flange of a connection end of each steel girder segment anda web; and a hinge assembly, installed to be attachable to a lowerflange of the connection end, for hinge-combining the connection end. 2.The modular steel bridge of claim 1, wherein the hinge assemblyincludes: a connecting plate installed to be connected to the lowerflange of the connection end by using bolts and nuts; and a combiningmember fixedly installed at the connecting plate and complementarilyhinge-combined by a hinge pivot.
 3. The modular steel bridge of claim 2,wherein the lower flange of the connection end and the connecting plateare formed with a plurality of bolt holes.
 4. The modular steel bridgeof claim 2, wherein the combining member includes: a first hinge platebeing fixedly installed at one connecting plate and having a pair ofcombining holes to which the hinge pivot is combined; and a second hingeplate being fixedly installed at another connecting plate, having acombining hole to which the hinge pivot is combined, and being combinedwith the first hinge plate in a concavo-convex manner.
 5. The modularsteel bridge of claim 2, wherein the hinge pivot is formed with pinholes into which hinge pins are inserted at each end thereof.
 6. Themodular steel bridge of claim 2, wherein the connecting plate isinstalled to be connected to the bottom part of the lower flange, andthe combining member is installed to be fixed to the bottom part of theconnecting plate.
 7. A modular steel bridge configured by connecting atleast two steel girder segments, comprising: a bearing block installedat a connection end of each steel girder segment; a hinge assemblyinstalled at the connection end; and a reinforcing unit being installedto be connected to each connection end and dividing the tensile forceapplied to the hinge assembly.
 8. The modular steel bridge of claim 7,wherein the bottom part of the web of the connection end is cut to apredetermined height, and the hinge assembly is installed to be fixed atthe cutting part of the web and the top part of the lower flange.
 9. Themodular steel bridge of claim 8, wherein the hinge assembly includes: afirst hinge plate installed to be fixed at the cutting part of the webof the connection end of one steel girder segment and the top part ofthe lower flange, and having a pair of combining holes to which a hingepivot is combined; and a second hinge plate installed to be fixed at thecutting part of the web of the connection end of another steel girdersegment and the top part of the lower flange, having a combining hole towhich the hinge pivot is combined, and being combined with the firsthinge plate in a concavo-convex manner.
 10. The modular steel bridge ofclaim 9, wherein the hinge pivot is formed with pin holes into whichhinge pins are inserted at each end.
 11. The modular steel bridge ofclaim 9, wherein the first hinge plate and the second hinge plateinclude a combining unit to which the hinge pivot is combined.
 12. Themodular steel bridge of claim 11, wherein the combining unit protrudesoutside the connection end and is extended between the lower flanges.13. The modular steel bridge of claim 7, wherein: the reinforcing unitincludes a steel rod installed to be connected to the lower flange ofeach connection end.
 14. The modular steel bridge of claim 13, whereinthe reinforcing unit includes: a fixing member being installed at thelower flange of each connection end and supporting respective ends ofthe steel rod; and a nut combined to each end of the steel rod.
 15. Themodular steel bridge of claim 7, wherein the reinforcing unit includes asteel plate installed to be connected to the lower flange of eachconnection end.
 16. The modular steel bridge of claim 15, wherein thereinforcing unit includes a connecting member being installed at eachlower flange and supporting the steel plate.
 17. The modular steelbridge of claim 16, wherein the steel plate is installed to be connectedto each connecting member by using bolts and nuts.
 18. The modular steelbridge of claim 16, wherein the steel plate is installed to be weldedand fixed to each connecting member.
 19. The modular steel bridge ofclaim 7, wherein the bearing block is fixedly installed to the upperflange of each connection end and web.
 20. The modular steel bridge ofclaim 1, wherein the connection ends of the steel girder segments arearranged with a gap therebetween, and the bearing blocks are installedto be contacted with each other.
 21. The modular steel bridge of claim1, wherein the bearing blocks are installed to protrude into a gap spacebetween the connection ends.
 22. The modular steel bridge of claim 1,wherein, regarding the steel girder segments, the upper flange of eachconnection end is cut to a predetermined length, and the top part of theweb of each connection end is cut to a predetermined height.
 23. Themodular steel bridge of claim 1, wherein each bearing block is formed tobe thicker than the upper flange, and is welded and fixed at the cuttingparts of the upper flange and the web.
 24. The modular steel bridge ofclaim 1, wherein the steel girder segment is an I-type girder.
 25. Themodular steel bridge of claim 1, wherein the steel girder segment is abox girder.
 26. The modular steel bridge of claim 1, wherein the steelgirder segment is a

-type girder.